     shot))
 
 (defmethod handle-collision :asteroid [{:keys [hit? size position speed] :as asteroid}]
-  (let [fragment-size (/ size sqrt3)]
+  (let [fragment-size (/ size fragment-size-reduction)]
     (if hit?
-      (create-asteroids 3 fragment-size position speed)
+      (create-asteroids fragment-number fragment-size position speed)
       asteroid)))
 
 (defmethod handle-collision :other [{hit? :hit? :as object}]

         debris? (< size asteroid-min-size)]
     {:type           (if debris? :debris :asteroid)

      :size           (vary asteroid-size-variance size)
      :shape          shape
      :color          (Color. 250 240 (if debris? 150 20))
      :paint-method   draw-polygon

; functional model
; ----------------------------------------------------------
; START: constants

(def width 120)
(def height 100)
